If you’ve tried all of the standard methods of bleeding your ATV brakes with no success, it’s time to try reverse bleeding them instead. The job is actually quite simple. This post will tell you three ways to do it step-by-step.

What is reverse bleeding?

With the standard methods of bleeding the brakes, you direct the stream of brake fluid down and out the bleed valve located on the brake caliper. This is the same direction witch the fluid moves when you operate the brakes in a normal riding situation.

In theory, the air trapped inside the system should be pushed out together with the brake fluid.

This downward flow of brake fluid is achieved either by pumping the brake lever or by connecting a vacuum device on the bleed valve to suck the fluid out of the system.

With reverse bleeding, on the other hand, the stream of brake fluid goes in the opposite direction.

The idea is quite simple.

Instead of pressing the brake fluid from the reservoir, down and out through the bleed valve, you find a way to press new fluid into the system through the bleed valve, from where it flows up back into the brake fluid reservoir.

bleed master cylinder air bubbles
Air bubbles appearing in the brake fluid reservoir is a good sign!

You can use a store bought tool to do this, or you can choose between some of the DIY solutions I describe in this post.

Why reverse bleed the brakes?

The standard method by repeatedly pumping the brakes and opening the bleed valve does not always work on smaller vehicles such as ATVs. Their small master cylinder will simply not push enough fluid to get the job done.

Air bubbles trapped in the system just end up being pushed back and forth within the brake line, and not completely out the bleed valve.

Even after vacuum bleeding your brakes, there still may be bubbles of air trapped inside the system.

So reverse bleeding reverses the stream of brake fluid. The air moves easier upwards as it doenæt has to fight gravity. The reverse stream of fluid will better reach pockets of trapped air as well.

Other benefits are speed and the possibility to do the job on your own with no helper. The job will be done in just a matter of minutes.

Possible downsides with reverse bleeding the brakes

There at least a dozen ways you can bleed the brakes on your ATV. All of them comes with some pros and cons to consider. Here are some possible downsides with reverse bleeding the brakes:

  • The brake fluid closest to the brake caliper is usually in bad shape due to heat. It may also be contaminated with debris. It is not ideal to send this fluid up and through the master cylinder. A way to partly avoid this is by using a pump that uses no more than about 10-12lbs of pressure. This should (at least in theory) ensure that debris stays down by the caliper.
  • If you’re not going DIY, the tools required does cost a few bucks. The price range between 60-400 dollars, depending on which brand and model you choose.

Different ways to reverse bleed the ATV brakes

Enough with the chit-chat. Let’s look at the different ways you can reverse bleed the brakes on your ATV.

Reverse brake bleeding tool

A variety of brands offer these types of tool, but they share the same basic design features.

They consist of a container where you put the new brake fluid, a hand pump that sucks the fluid out of the container and press it into the bleed valve, and some tubing, fittings, and connectors to tie it all together.

Alternatively, you find systems that connect to the master cylinder and uses vacuum to suck brake fluid up the reverse way. Some systems can even do both.

Tools required

  • A reverse bleeding tool of your preference.
  • An 8mm wrench and a hex bit that fits the lid of your master cylinder.
  • A syringe or a turkey baster.
  • New brake fluid according to factory specifications. The correct type should be marked on the reservoir cover.

How to use the tool (General directions. The procedure may vary depending on what tool you get):

  • Open the lid of the master cylinder to remove excess fluid. Use a syringe or a turkey baster.
  • Assemble the tool according to manufacturer directions.
  • Prime the tool with fresh brake fluid so that no air is trapped inside. Pump until clear fluid squirts out of the connector end of the tool.
  • Immediately connect the tool to the bleed valve.
  • Open the bleed screw.
  • Squeeze the handle about 6-8 times on the first wheel, then 5-6 on the other three. Keep an eye in the master cylinder so you don’t overflow it. And don’t press too hard on the handle, or you’ll create a mess up by the master cylinder.
  • Use a cheap syringe connected to a piece of clear tubing or a turkey baster to suck up excess brake fluid from the master cylinder.
  • When done pumping, remove the connector from the bleed valve and leave it open for a second or two. The pressure inside the brake system will press out any air close to the bleed valve.
  • As soon as you see clear fluid coming out, close the bleed valve.

Use an oil squirt can (DIY)

If you’re looking to keep your costs down, you can also get the job done with just a few cheap tools and parts that you find in any automotive store. This first DIY way of doing this job is by using a basic oil squirt can.

Tools and parts required

  • A completely clean oil squirt can. These are cheap, so you might as well get a new one for the job. It’s not worth the risk of getting anything else than clean brake fluid inside the brake system.
  • A few feet of 5/16 inch clear vinyl tubing that fits over the brake bleed valve. 5/16 inch diameter will be fine.
  • An 8mm wrench and a hex bit that fits the lid of your master cylinder.
  • A large syringe with a piece of clear tubing or a turkey baster.
  • Pliers

How to do it

  • Remove the reservoir cover and diaphragm so that you can remove excess brake fluid when adding fresh fluid from the caliper side.
  • Connect a piece of vinyl tubing to the nozzle of your oil squirt can. Use a hose clamp or a zip tie to secure it in place.
reverse bleed atv brakes oil squirt can diy
Use some pliers to fasten the zip-tie properly.
  • Completely fill your oil squirt can with new brake fluid and give it a few pumps until clear fluid squirts out of the hose.
  • Put your 8mm wrench on the bleed valve. Do not open it yet.

Connect the hose to the bleed valve. Make sure there are no air bubbles in the hose before you connect it. Use another zip tie to keep it in place. Use some pliers to get it properly snugged down.

fasten hose bleed valve zip tie
It is important that both ends of the hose are properly fastened or they may come off when you start pumping.
  • Open the brake bleeder about a quarter to half a turn.
  • Start gently pumping fresh fluid into the system. Do not press hard. Take your time and press just enough to see the level rising up in the reservoir.
reverse bleed atv brakes
The hose should be full of brake fluid when you start pumping. My brakes were fine so this pic is just to demonstrate the setup.
  • Use the syringe to remove excess brake fluid from the reservoir. Continue pumping until all of the fluid is replaced.
turkey baster brake fluid reservoir
Remove excess brake fluid before it spills.
  • Tighten the bleed valve and repeat on the other three tires.
  • Finish off by making sure you have the right amount of brake fluid inside your reservoir, and then replace the lid and diaphragm.

Reverse bleeding using a syringe

Tools and parts required

  • Two large syringes (preferably 50ml or bigger), where at least one of them is completely clean. You can get these at automotive stores or pharmacies for just a few dollars.
  • A few feet of 5/16 inch clear tubing.
  • Some zip ties.
  • Brake cleaner and a rag.
  • New brake fluid according to factory specifications.
  • Pliers.

How you do it

  • Remove the reservoir cover and rubber diaphragm.
  • Use one of the syringes to remove the brake fluid that’s in the brake fluid reservoir.
  • Put your 8mm wrench on the bleed valve. Do not open it yet.
  • Connect a couple of feet of tubing to your other syringe. Use a zip tie to tighten the tube to the outlet of the syringe. This is to prevent it from popping off when you apply pressure.
  • Fill the other syringe with new fresh brake fluid, and connect it to your bleed valve.
    Again, use a zip tie to keep it in place.
reverse bleed atv brakes syringe
Make sure there are no air bubbles inside the syringe or tube.
  • Before you start injecting brake fluid, you need to make sure there is no air in the tube. Hold the syringe upright and tap the tube until all of the air has moved up and into the syringe.
  • Open the bleed valve about a quarter to half a turn.
  • Start gently compressing the plunger on the syringe to pump brake fluid into the system. Take your time and do not press too hard or you will end up popping the tube off and you need to start all over again.
reverse bleed atv brakes syringe diy
Do not press too hard. Take your time!
  • You will likely have a small amount of fluid leaking out. Have a cloth or paper towel ready to clean it up.
  • Keep an eye on your reservoir. Stop pressing when it is getting full. Use the other syringe to remove excess fluid before you continue. You can use a piece of wire to hang the syringe containing fresh fluid when you are removing the old.
  • Continue this process until all of the fluid is replaced.
  • Tighten the bleed valve and remove the hose.
  • Clean off any spilled brake fluid. Spray the caliper and the area around the master cylinder with brake cleaner to make it completely clean.

If you’re still having problems bleeding the brakes on your ATV, I recommend having a look at this post where I give all of the best tips I have learned about stubborn brakes that won’t bleed properly.